AB0679 INTRAVENOUS INMUNOGLOBULIN IN INFLAMMATORY MYOPATHIES: EXPERIENCE OF A SINGLE REFERRAL CENTER
Authors: C. Corrales-Selaya, F. Benavides-Villanueva, A. Herrero-Morant, D. Prieto-Peña, A. Corrales, M. A. González-Gay, R. Blanco
Journal: Annals of the Rheumatic Diseases (2022)

Background Treatment of inflammatory idiopathic myopathies (IIM) is not well-stablished. Although the mechanism of action of intravenous immunoglobulins (IVIG) is not completely understood, they may be useful in rheumatic diseases, including IIM. Objectives To assess the efficacy and safety of IVIG in IIM. Methods Observational Single University study of IIM requiring therapy with at least one cycle of IVIG from January 2000 to December 2021. IIM, was diagnosed according to EULAR/ACR classification criteria (1). Efficacy outcomes were a ) clinical features (muscular strength and cutaneous involvement), b ) analytical parameters (Creatine Kinase) and, c ) glucocorticoid-sparing effect. All of them were measured at 2-4 weeks, 3 months, 6 months, 1 year and 2 years after IVIG onset. Muscular Strength was measured in three muscle areas (upper limbs, lower limbs and neck flexor muscles) by using Medical Research Council Grading System. We classified clinical outcomes (muscular strength and dermatological) improvement in 3 categories: Complete improvement, Partial improvement and No improvement. IVIG schedule was a total of 2 g/kg administered in 1-5 days. Results We included 28 patients (22 females, mean age; 47.07±26.71 years) with IIM. The main clinical features are summarized in Table 1. Muscular weakness was present in 18 patients and cutaneous manifestations in 18 patients at baseline. Table 1. General features of 28 patients with inflammatory idiopathic myopathies with IVIG treatment GENERAL FEATURES GENERAL FEATURES (continuation) Gender female / male, n (%) 22(78.6) / 6 (21.4) Clinical manifestations at IVIG onset; n (%) Age (mean±SD) 47.07±26.71 Upper limbs involvement 17 (60.71) Underlying IIM; n (%) Lower limbs involvement 17 (60.71) Dermatomyositis 12 (46.42) Neck flexors muscular involvement 14 (50.00) Amyopathic Dermatomyositis 1 (3.57) Cutaneous involvement 18 (64.28) Juvenile Dermatomyositis 6 (21.42) Dysphagia 8 (28.57) Polymiositis 2 (7.14) Constitutional symptoms 9 (3.14) Inmune-mediated necrotizing miopathy 5 (17.85) Malignancy 2 (7.14) Systemic sclerosis/myositis overlap syndrome 1 (3.57) Respiratory disease 3 (10.71) Toxic myopathy 1 (3.57) Articular involvement 4 (14.28) IIM duration, months (mean±SD) 28.74±38.75 Cutaneous vasculitis 2 (7.14) Previous immunosupressants before IVIG; n (%) Methotrexate 9 (32.14) Concomitant Therapy with IVIG ; n (%) Azathioprine 4 (14.28) Oral Corticosteroids at IVIG onset 18 (64.28) Cyclophosphamide 1 (3.57) Methotrexate 10 (35.71) Mycophenolate mofetil 2 (7.14) Azathioprine 4 (14.28) Hydroxychloroquine 5 (17.85) Mycophenolate mofetil 1 (3.57) Rituximab 1 (3.57) Hydroxychloroquine 5 (17.85) Plasmapheresis 1 (3.57) An early and maintained improvement was observed in all outcomes: clinical (muscular strength (a) and cutaneous manifestations (b)), Creatine Kinase (c) and glucocorticoid-sparing effect (d) (Figure 1). Figure 1. Efficacy Outcome. Figure 1. *p&lt; 0.05 (Wilcoxon test). After two years of follow-up, we observed the following adverse effects: headache (n=6), pruritus (n=3), allergic reaction (n=2) and arterial hypertension (n=1). No heart failure, renal insufficiency or thrombotic events were found. Conclusion IVIG seems effective and safety in IIM treatment. References [1]Lundberg, et al. Ann Rheum Dis 2017:76; 1955-1964. Disclosure of Interests None declared